Anyhow...If I were to relate Foursquare and its value to any recent acquisition it would be to Waze. Waze does have some degree of ads, but going out on a limb, I would venture to guess they are pretty negligible. Others may argue that Waze has all this valuable crowd sourced traffic data, well I don't think that data has been or will be monetized either. So what is the value of Waze that justifies a >$1B acquisition? In my estimation, it is the same thing as Foursquare (if not now, at one point should have had), due to their user base and the nature of the app, by default both Waze and Foursquare are cartographers and there is real money/value in that, and I am surprised of >100 comments I didn't see one mentioning that.
Because of the cost involved, there are only a handful of true map makers in the World, and from what I can tell they are all Billion dollar + companies. Waze (and Foursquare) both found novel ways to propel themselves into the space...and on the backs of their users, not with the traditional investment of satellites/GPS technology. If anyone anywhere creates an App that has millions of users who are updating geocentric data in real time from their own users and not paying for this data...I wouldn't be to concerned with ads for its own sake, just losing my user base.